1. Field of the Invention
The present invention relates to lubricating oil compositions for food processing machines and more particularly to such a composition having excellent properties and comprising a saturated fatty acid glyceride as the base oil and at least one fatty acid as the essential component.
2. Prior Art
Various food processing machines have heretofore been used in all steps for producing foodstuffs from raw materials such as agricultural, live-stock and marine products by their fine selection, classification, grinding, mixing, roasting, heating, fermentation, boiling condensation, drying and freezing. The main machines include agricultural products-processing machines such as a machine for polishing rice or wheat, a machine for milling grains, a fermentation machine for producing rice wine, soy or miso, a machine for making noodle, a machine for making bread, a machine for making cakes and a processing machine for preparing juices, jams or pickles; live-stock products-processing machines such as a milk-processing machine, a machine for preparing dairy goods such as cheese and butter and a meat processing machine for preparing ham and sausage; a marine products-processing machines such as a fish-processing machine and a seaweeds-processing machine; and machines for preparing additives for food, natural flavors and pharmaceutical goods, such as a vacuum film evaporator and a machine for kneading.
As the above food-processing machine are used for preparing foodstuffs and creating favorite tastes for human beings, they should receive careful attention to confirm that they are safe and hygienic for said purpose.
Accordingly, from the standpoint of safety, animal and vegetable oils as well as liquid paraffin have been used as a lubricating oil for application to the bearings, gears, sliding guide surfaces and oil pressure systems of food processing machines
However, in case of using animal and vegetable oils, there are problems as to oxidation stability, rust prevention or corrosion resistance. On the other hand, in case of using liquid paraffin, there are problems as to low-temperature characteristics and lubricity and, furthermore, it contains aromatic compounds, though in a very small amount, which are harmful for human bodies, because it is an oil obtained by refining a mineral oil. Consequently, for food additive uses, liquid paraffin used only as a releasing agent for bakery uses in the field of food industry. Thus, development of new types of lubricating oils having superior properties to those of the conventional oils such as animal and vegetable oils or liquid paraffin, has been required